Antistatic photographic film



A. F'. SIILZER.

ANTISTATIC PHOTOGRAPHIC FILM.

APPLICATION FILED FEB. 21, 1921.

Lkp Patented Oct. l?, 1922.,

Fi I E a SWW ATTORNEY Patented @eto il?, i222.,

entre ALB@ JF. SU

@TENT @FFME 0F RGCHEST, NEW YORK, ASSIGNOR T0 EASTMN KODAK COMPANY, 0F RQCHESTER, NEW YORK, A. CORPORATION 0F NEW YON'.

I ANTISTATIC PHOTOGPHIC IFILM.

Application filed February 21, 1921'. Serial No. 446,783.

To all wkomz'tma' concewz: A

Beit known t at l, ALBERT F. SULzm, a citizen of the United States of merlca, residin at Rochester, in the county of Monroe an State of New York, have invented certain new and useful Improvements in Antistatic Photographic Films', of which the following is a full, clear, and exact speclcation.

rThis invention relates to photographic rllhe princi al object of this mvention is to provide a fi m having the usual qualities essential in commercial practice, which will also be so constituted that markings, due to electrical discharges, are 4prevented or minimized to a harmless amount. @ther objects will hereinafter appear.

Due to the manipulation of sensitive photographic lm, some times in manufacture, but more frequently in use, characterlstlc lines or patches may appear on development, because of electrical discharges which are created during the handling. rlhe fog or fog lines which are thus formed on the. film are particularly noticeable in the case of the standard species of motion plcture film, which includes a nitrocellulose support or base. llt is very important from the commercial standpoint to prevent this defect in the motion plcture art, particularly when making negative lm strips. 'The trouble is commonly referred to as static and will be so designated herein.

While certain camera modications for preventing this electrical trouble have been roposed, it is very desirable to prevent static y a proper constitution of the film, so that the latter may beemployed in any commercial camera without any precautlons being taken by the user. @f course, the film should likewise be ca able of subsequent fluid treatment and drying on the customary racks or apparatus without injury.

l have discovered that film having unexpectedly strong anti-static properties' may be prepared by incorporating in rits support a layer containing an ether of cellulose and cellulose acetate. rllhis invention is a specic application of the broader discovery disclosed 1n my co-pending application filed of even date herewith, Serial No. 446,782. The composition hereinafter described is claimed in my co-pending divisional application Serial No, 543,531, filed Mar. 13|,

1922, for composition for making anti-static photographic film.

ln the accompanying drawing,-

Fig. l isa sectional View on an exaggerated scale of the preferred embodiment of my invention;

Fig. 2 is a sectional View on an exaggerated scale of a modification of the invention.

ln the drawing, 2 represents the support of any customary type, such as a exble transparent base of nitrocellulose, containing softening substances and modifying agents if desired. Upon the support 2 is a p otographicall sensitive layer 1 which is preferably of t e usual silver-haloid emuls1on t pe. 3 is my anti-static layer or backing, t is being located, in the preferred form of my invention, on the base or support 2 whlch is opposite to the sensitive layer l.

The ether-containing layer 3 may be located between the support 2 and sensitive layer 1, as shown in Flg. 2, but this is not the preferred form of my invention, although useful photographic film may be made in that way.

ln preparing a composition for forming the coating 3, ll find it best to dissolve the cellulose ether and the cellulose acetate separately, the two solutions being then mixed and finally diluted ifdesired. rl`he following proportions and solvents are useful, but,

of course, may be widely varied. rlhe pro-l portions are by weight. l may dissolve 45 parts of ethyl cellulose, of the kind which is insoluble in water and not injuriously softened by the latter, in 50 parts of ethyl alcoholl and 900 parts of chloroform. l separately dissolve 45 parts of acetone-soluble cellulose acetate in suiicient acetone to make a clear solution. l then combine the acetate and ether solutions into a homogeneous composition. The latter may then be diluted with a mixture of acetone and ethyl alcohol until the acetone content becomes say 4000 parts' and the alcohol may amount to 550 parts. by using this method of mixing, a properly diluted Howable composition is provided which sets quickly when coated upon the film support, the volatile ingredients passing away and leaving a transparent,

Maese? Having thus described my invention, what 3. A photographic film comprising a sup- I claim as new and desire to secure by Letport containing cellulose nitrate, a photo- 15 ters Patent is: j graphically sensitive layer carried thereby 1. A photographic film comprising a film -and a backing comprising an ether of cellu- 5 support, a photographically sensitive layer lose and cellulose acetate.

carried thereby, and a layer, comprising an 4:. A photographic film comprising a supether of cellulose and celluloseacetate, port of cellulose nitrate, a photographically 20 2. A photographic film comprising-a film sensitive layer carried thereby, and a backsupport, which tends to produce static, a ing comprising water-insoluble ethyl cellu- 10. photographically sensitive layer' carried lose and acetone-soluble cellulose acetate. thereby and an anti-static backing compris'- Signed at Rochester, New York, this 14th ing ethyl cellulose and acetone-soluble celluday of February, 1921. lose acetate. ALBERT F. SULZER. 

